Evaluation of venous valvular function of the lower limb by duplex ultrasonography

ABSTRACT

The duration of reverse flow after release of manual calf compression was measured in the common femoral, long saphenous, popliteal and short saphenous veins in 27 patients with venous disease of the lower limb by duplex ultrasonography. Fifteen controls without venous disease were assessed also. Before undertaking the study, the reproducibility of the technique was evaluated in 6 subjects by repeating the examination over 3 consecutive days, the coefficient of variation of the test was 7.3%. The 95% confidence interval [c.i.] of the median [0.16 s] of all measurements in the normal limbs was 1.12 - 0.18 s. In limbs with clinical evidence of venous disease at least one of the sites examined was found to have reverse flow longer than 0.5 s. These data suggested that the measurement of reverse flow after release of manual calf compression is a reproducible technique. While, the method records some reverse flow in normal veins, its duration is unlikely to exceed 0.5 s, significant reflux is therefore defined as reverse flow exceeding 0.5 s